Round a decimal to the nearest half

gistfile1.php

<?php

/**
 * Round a decimal to the nearest half, so:
 *   0   becomes 0
 *  0.2  becomes 0 
 *   1   becomes 1
 *  2.5  becomes 2.5
 *  2.51 becomes 2.5
 *  2.49 becomes 2.5
 *  4.9  becomes 5
 * 
 * @param float $decimal
 * @return float
 */
function roundToHalf($decimal) {
	return round($decimal / 0.5) * 0.5;
}

?>